Single-molecule folding mechanisms of the apo- and Mg(2+)-bound states of human neuronal calcium sensor-1

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dc.citation.issue1
dc.citation.volume109
dc.contributor.authorNaqvi MM
dc.contributor.authorHeidarsson PO
dc.contributor.authorRodriguez Otazo M
dc.contributor.authorMossa A
dc.contributor.authorKragelund BB
dc.contributor.authorCecconi C
dc.coverage.spatialUnited States
dc.date.available2015-07-07
dc.date.available2015-05-20
dc.date.issued2015-07-07
dc.description.abstractNeuronal calcium sensor-1 (NCS-1) is the primordial member of a family of proteins responsible primarily for sensing changes in neuronal Ca(2+) concentration. NCS-1 is a multispecific protein interacting with a number of binding partners in both calcium-dependent and independent manners, and acting in a variety of cellular processes in which it has been linked to a number of disorders such as schizophrenia and autism. Despite extensive studies on the Ca(2+)-activated state of NCS proteins, little is known about the conformational dynamics of the Mg(2+)-bound and apo states, both of which are populated, at least transiently, at resting Ca(2+) conditions. Here, we used optical tweezers to study the folding behavior of individual NCS-1 molecules in the presence of Mg(2+) and in the absence of divalent ions. Under tension, the Mg(2+)-bound state of NCS-1 unfolds and refolds in a three-state process by populating one intermediate state consisting of a folded C-domain and an unfolded N-domain. The interconversion at equilibrium between the different molecular states populated by NCS-1 was monitored in real time through constant-force measurements and the energy landscapes underlying the observed transitions were reconstructed through hidden Markov model analysis. Unlike what has been observed with the Ca(2+)-bound state, the presence of Mg(2+) allows both the N- and C-domain to fold through all-or-none transitions with similar refolding rates. In the absence of divalent ions, NCS-1 unfolds and refolds reversibly in a two-state reaction involving only the C-domain, whereas the N-domain has no detectable transitions. Overall, the results allowed us to trace the progression of NCS-1 folding along its energy landscapes and provided a solid platform for understanding the conformational dynamics of similar EF-hand proteins.
dc.description.publication-statusPublished
dc.format.extent113 - 123
dc.identifierhttps://www.ncbi.nlm.nih.gov/pubmed/26153708
dc.identifierS0006-3495(15)00540-8
dc.identifier.citationBiophys J, 2015, 109 (1), pp. 113 - 123
dc.identifier.doi10.1016/j.bpj.2015.05.028
dc.identifier.eissn1542-0086
dc.identifier.elements-id255663
dc.identifier.harvestedMassey_Dark
dc.languageeng
dc.publisherBiophysical Society
dc.relation.isPartOfBiophys J
dc.relation.urihttps://www.sciencedirect.com/science/article/pii/S0006349515005408?via=ihub
dc.rightsElsevier user license
dc.subjectCations, Divalent
dc.subjectComputer Simulation
dc.subjectEscherichia coli
dc.subjectHumans
dc.subjectKinetics
dc.subjectMagnesium
dc.subjectMarkov Chains
dc.subjectNeuronal Calcium-Sensor Proteins
dc.subjectNeuropeptides
dc.subjectOptical Tweezers
dc.subjectProtein Folding
dc.subjectSpectrum Analysis
dc.subjectThermodynamics
dc.subject.anzsrc02 Physical Sciences
dc.subject.anzsrc03 Chemical Sciences
dc.subject.anzsrc06 Biological Sciences
dc.titleSingle-molecule folding mechanisms of the apo- and Mg(2+)-bound states of human neuronal calcium sensor-1
dc.typeJournal article
pubs.notesNot known
pubs.organisational-group/Massey University
pubs.organisational-group/Massey University/College of Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Fundamental Sciences
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